[filmscanners] Re: Advice on scanner settings

["Preston Earle" <PEarle@triad.rr.com>]

"Carlisle Landel" asks several questions about scanning, including: "I'm
planning on 4000 dpi for maximum resolution, with 3 samples and the color
analog gain set at 1 for all colors." and  "With respect to output, I gather
that TIFF is better than JPEG,
because JPEG is compressed.  Is that right?"
---------------------------------
I think the scan resolution should be determined by how you plan to use the
final images. A 4000ppi scan will give a file capable of being printed to up
to 17" x 25". If all you want to do with most files is display them on a
screen or make 4x6 prints, 4000ppi is overkill, and you will spend a lot of
time cleaning up raw scans and a lot of effort resizing large files for
their intended purpose. You may want to scan any "museum quality" images at
4000ppi, but most others could be done at 2700ppi or so. Even that is
overkill for most purposes. If you have images that need severe cropping,
you might want to do the raw scan at 4000ppi and then crop the for the area
of interest before spending a lot of time cleaning the whole scan.

As to the scanner settings, I'd try a number of samples at different
settings and see which were best. The best settings may well be dependant on
the image content of each slide. I never saw much benefit from multiple
passes but YMMV.

As to file format, I'd use jpeg. A 4000ppi 35mm scan will be about 20 megs
in size. A good quality JPEG will be 2-2.5 megs and a 2700ppi JPEG will be
about 1 meg. With 2700ppi JPEGS, I can keep my 12,500 image archive in 10
Gigs of hard disk. If they were 4000ppi tiffs it would be 250 Gigs, and I
don't believe the files would be any more useful.

The biggest drawback to JPEGs is in files that do not have sufficient
resolution. That will not be the case for your images.

If you haven't downloaded the Polaroid Dust and Scratches filter from
http://www.polaroid.com/service/software/poladsr/poladsr.html you should try
it. It isn't intuitive and takes some experimentation, but it is pretty good
at cleaning up minor imperfections in scans.

Preston Earle
PEarle@triad.rr.com
www.sawdustforbrains.blogspot.com


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